Hi there!
We were also there the first week of February this past year, and it was downright cold at times. Not to let that scare you, but so that you'll be prepared. We actually had frost two nights of our trip (of course it was 80 the previous week AND the week after - GAH!). You really never, ever can tell what the weather will be like, until you get there.
I am a bit of a weather watcher, and I was faithfully keeping track of the weather for the week of our trip, and literally up until the morning we left, it was saying that most days would be in the 70's... if I hadn't checked it right as I was zipping up my suitcase, I would never have seen those couple days that dipped down into highs of low 50's and 30's in the evenings/mornings. Needless to say, I threw a few more things in the bag and was OH SO HAPPY for them.
My recommendation is to actually bring thin gloves and hats for everyone (tho the hubs probably won't need or wear - at least in my experience

), a couple of good, heavy fleece tops/zippies, and decently heavy long pants, plus all the regular t-shirts, capris, etc. I have silk long johns, and took a couple of the tops and one of the pants, and actually wore a set under my park gear one day (48 was the high!). We still had a great time, but every morning, folks were raiding my suitcase for warmer clothes.
Avoid cottony stuff for your outermost gear - it's heavier, bulkier and if it gets wet (it might shower), it will only retain the cold and never dry out... fleece/microfleece holds in heat better, is light, packs down to nothing and will still insulate if it gets wet. And, Old Navy sells it for cheap.
While the weather wasn't what we'd wanted, we still had such a great time!!! So will you!!